The application's broad, long-term objectives are to develop a rapid, high-throughput clinical assay for 3' fibrinogen that will be used to assess the risk of a patient developing venous thromboembolism. This assay will guide clinical management, particularly the use of long-term anticoagulant therapy for patients. The utility of this assay will be the identification of patients at risk for developing venous thromboembolism who should be anticoagulated, and conversely, identification of patients at low risk of developing venous thromboembolism who should not be subjected to the possible dangers of anticoagulant therapy. The specific aim of Phase I of this Fast-Track application is to: 1) Develop a rapid, high-throughput assay for 3' fibrinogen. This will be accomplished using our proprietary monoclonal antibody, 2.G2.H9, and the Luminex xMAP(R) technology platform. The milestones for the successful completion of Phase I and transition to Phase II are to develop a 3' fibrinogen assay that measures the normal range of 3' fibrinogen in plasma from 0-1.5 mg/ml, and achieves a standard curve fit with an R2 accuracy of >0.95. In Phase II, the Specific Aims are to: 2) Validate the 3' fibrinogen assay. The assay will be evaluated for linearity, interference testing, method comparison, bias estimation, and comparison to the previous plate-based ELISA in test samples using guidelines published by the Clinical and Laboratory Standards Institute (CLSI) for precision performance of quantitative measurement methods. This information will be essential for Food and Drug Administration (FDA) and Clinical Laboratory Improvement Amendments (CLIA) evaluation of the assay; 3) Quantitate the intra-individual variability of 3' fibrinogen levels over time. This will be accomplished by measuring 3' fibrinogen levels in individuals at weekly time points over a 3-month period and monthly time points over a one-year period to determine the within-subject variability. This information will be critical for widespread acceptance of the assay by clinical laboratories; 4) Scale up production of the assay kit components. This will be accomplished with assistance from the Office of Technology Transfer & Business Development at OHSU, which has forged ties with the entrepreneurial and local business community to create a framework of support for the development of companies utilizing OHSU research. Their Springboard Program is designed to catalyze the development of new ventures based on OHSU technologies. We have already attracted the interest of Diagnostica Stago, a major international coagulation diagnostics company. PUBLIC HEALTH RELEVANCE: This proposal is to develop a rapid, high-throughput clinical assay for 3' fibrinogen, a newly-emerging risk factor for venous thromboembolism. This assay will be used by physicians for risk assessment of venous thromboembolism, and will guide their clinical management, particularly their use of anticoagulant therapy in patients. Information gained from the use of this assay will identify patients at risk for deep vein thrombosis who should be anticoagulated, and conversely, will identify patients at low risk of venous thromboembolism who should not be subjected to anticoagulant therapy.